From 245e356449dc3c66d76157f3ddf1cc82aa6e35dd Mon Sep 17 00:00:00 2001
From: catskul <catskul@users.noreply.github.com>
Date: Tue, 25 Apr 2017 03:34:17 -0400
Subject: [PATCH] Const-ify ProbabilityGrid::ToProto (#238)

---
 cartographer/mapping_2d/probability_grid.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/cartographer/mapping_2d/probability_grid.h b/cartographer/mapping_2d/probability_grid.h
index 2d7e4cc..e72a34d 100644
--- a/cartographer/mapping_2d/probability_grid.h
+++ b/cartographer/mapping_2d/probability_grid.h
@@ -171,7 +171,7 @@ class ProbabilityGrid {
     }
   }
 
-  proto::ProbabilityGrid ToProto() {
+  proto::ProbabilityGrid ToProto() const {
     proto::ProbabilityGrid result;
     *result.mutable_limits() = cartographer::mapping_2d::ToProto(limits_);
     result.mutable_cells()->Reserve(cells_.size());